Acute diarrhoeal diseases are among the leading causes of mortality in infants
and young children in many developing countries. In most cases, death is
caused by dehydration. Dehydration from diarrhoea can be prevented by giving
extra fluids at home, or it can be treated simply, effectively, and cheaply in
all age-groups and in all but the most severe cases by giving patients by
mouth an adequate glucose-electrolyte solution called Oral Rehydration Salts
(ORS) solution.

During diarrhoea there is an increased loss of water and
electrolytes (sodium, chloride, potassium, and bicarbonate) in the liquid
stool. Water and electrolytes are also lost through vomit, sweat, urine and
breathing. Dehydration occurs when these losses are not replaced adequately
and a deficit of water and electrolytes develops. The volume of fluid lost through the stools in 24 hours can vary from 5 ml/kg
(near normal) to 200 ml/kg, or more. The concentrations and amounts of
electrolytes lost also vary. The total body sodium deficit in young children
with severe dehydration due to diarrhoea is usually about 70110 millimoles per
litre of water deficit. Potassium and chloride losses are in a similar range.
Deficits of this magnitude can occur with acute diarrhoea of any etiology. The
most common causes of dehydration are rotavirus, enterotoxigenic Escherichia coli
(ETEC) and, during epidemics, Vibrio cholerae
O1 or O139. Dehydration is the loss of water and salts from the body. The human body needs water to maintain enough blood and other fluids to
function properly. Along with the fluids, the body also needs
electrolytes, which are salts normally found in blood, other fluids, and
cells. The body may lose fluids in a variety of ways:

when urinating

when you vomit or have diarrhoea

when sweating

from the lungs during normal breathing.

If the body loses a substantial amount of fluids and salts
and they are not quickly replaced; for example: by drinking, the body starts
to "dry up" or get dehydrated. Severe dehydration can cause death. The usual causes of dehydration are a lot of diarrhoea
and vomiting. Dehydration can also occur if you do not eat or drink much
during an illness or if you do not drink enough during or after strenuous
exercise. Medications that cause fluid loss to control excess body fluid
(diuretics) are a common long-term cause. Although anyone can become dehydrated, those who become dehydrated the most
easily are:

babies under 1 year old

the elderly

anyone who has a fever

people in hot climates.

Dehydration caused by diarrhoea is one of the
biggest single killers of children in the modern world and diarrhoea itself is one of the
major causes of nutritional loss and poor growth.This year, about 2.2
million children will die of dehydration caused by diarrhoea -
80% of them in the first two years of their life. What
are the symptoms of dehydration? The degree of dehydration is graded according to signs and symptoms that
reflect the amount of fluid lost:

In the early stages of dehydration, there are no signs or symptoms. Early features are difficult to detect but include dryness
of mouth and thirst

lack of elasticity of the skin (when a bit of skin lifted up stays folded
and takes a long time to go back to its normal position)

rapid and deep breathing - faster than normal

fast, weak pulse

In severe dehydration, these effects become more pronounced
and the patient may develop evidence of hypovolaemic shock, including: diminished
consciousness, lack of urine output, cool moist extremities, a rapid and feeble pulse (the
radial pulse may be undetectable), low or undetectable blood pressure, and peripheral
cyanosis. Death follows soon if rehydration is not started quickly.

Dehydration

Dehydration (hypohydration) is the removal ofwater (hydor
in ancient
Greek) from an object. Medically,
dehydration is a serious and potentially life-threatening condition in which
the body contains an insufficient volume of water for normal functioning.

The term "volume depletion" is similar to dehydration, but it refers to the
loss of salts as well as water. Also see
Hypovolemia.

Dehydration symptoms generally become noticeable after 2% of one's normal
water volume has been lost. Initially, one experiencesthirst and
discomfort, possibly along with loss ofappetite
and dry skin.Athletes
may suffer a loss of performance of up to 50%, and experience
flushing, low endurance, rapidheart
rates, elevated body temperatures, and rapid onset of
fatigue.

The symptoms become increasingly severe with greater water loss. One's
heart and
respiration rates will increase to compensate for decreased
plasma volume and
blood pressure, while body temperature may rise because of decreased
sweating. Around 5% to 6% water loss, one may become groggy orsleepy,
experience headaches ornausea, and
may feel tingling in one's limbs (paresthesia).
With 10% to 15% fluid loss, muscles may become spastic, skin may shrivel and
wrinkle, vision may dim, urination will be greatly reduced and may become
painful, and delirium may begin. Losses of greater than 15% are usually fatal.
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Treatment

Correction of a dehydrated state is accomplished by the replenishment of
necessary water and electrolytes (rehydration).
Even in the case of serious lack offresh
water (e.g. atsea or in adesert),drinkingseawater
or urine does
not help, nor does the consumption ofalcohol. It
is often thought that the sudden influx ofsalt into the
body from
seawater will cause the
cells to dehydrate and thekidneys to
overload and shut down but it has been calculated that average adult can drink
up to 0.2 liters of seawater per day before the kidneys start to fail.

When dehydrated, unnecessarysweating
should be avoided, as it wastes water. If there is only dry food, it is better
not to eat, as water is necessary fordigestion.
The best treatment for minor dehydration is consumption of an
electrolyte-balanced fluid like a sports drink. For severe cases of
dehydration wherefainting,
unconsciousness, or any other severely inhibiting symptom is present (the
patient is incapable of standing or thinking clearly), emergency attention is
required. Fluids will be given through an IV, and within a few hours, the
patient will return to normal unless a complication occurs.

During vigorous exercise or in a hot environment, it is easy to lose
several times this amount. Heavy exercise in high temperatures could cause the
loss of over 2.5 litres of fluid per hour, which exceeds the body's absorptive
capacity.